The objective of the present work is to identify the land-cover and land-use changes derived from irrigation project Pujal-Coy setting, east of San Luis Potosi' state, Mexico. The study is based on the interpretation and analysis of satellite images Landsat MSS and ETM+, official and historical documents of the irrigation project and field work. The results indicate that during the initial stage of the project, more than 73 000 ha of deciduous tropical low forest, tropical dry forest and semi evergreen forest were cut dawn. The deforestation annual rate calculated for this period was 11%. At the moment, just 10 200 ha of dispersed fragments of forest persist in the three municipalities, as well as 64 remainders of arboreal vegetation with different disturb level. The proportion of the area occupied by grasslands growth from 21% in 1973 to more than 64% in the year 2000, while the cultivated areas maintain the same marginal surface that they had to the beginning of the project. These data evidence the unequivocal return of the extensive cattle raising that was sought to substitute with intensive agriculture, and the high environmental costs that of the project.